For encryption, it is slower than AES-GCM, because achieving nonce-misuse resistance requires, by definition, two (serialized) passes over the data. Nevertheless, optimized implementations run GCM-SIV (for 128-bit keys) at less than one cycle per byte on modern processors (roughly 2/3 of the speed of nonce-respecting AES-GCM). On the other hand, GCM-SIV decryption runs at almost the same speed as AES-GCM.

The QUIC working group has just been chartered, and will meet for the first time in Seoul. This working group is taking Google’s pre-standardization QUIC protocol that has been deployed in production for several years, and will use it as a starting point to develop a UDP-based, stream-multiplexing, encrypted transport protocol with standardized congestion control, TLS 1.3 by default, a mapping for HTTP/2 semantics over QUIC, and multipath extensions. This is the IETF’s first standardized always-encrypted transport protocol, so careful consideration of applicability and operational capabilities will be key for success.

In a nutshell, BBR creates an explicit model of the network pipe by sequentially probing the bottleneck bandwidth and RTT. On the arrival of each ACK, BBR derives the current delivery rate of the last round trip, and feeds it through a windowed max-filter to estimate the bottleneck bandwidth. Conversely it uses a windowed min-filter to estimate the round trip propagation delay. The max-filtered bandwidth and min-filtered RTT estimates form BBR's model of the network pipe.

Since no one has QUIC support enabled by default in the client, you're probably still safe to run it and enable QUIC in your own browser(s). (Update: since Chrome 52, everyone has QUIC enabled by default, even to non-whitelisted domains)

再來是 QUIC 走 UDP/443：

Well, if we want to allow the QUIC protocol, we will need to allow 443/UDP too.

Today, roughly half of all requests from Chrome to Google servers are served over QUIC and we’re continuing to ramp up QUIC traffic, eventually making it the default transport from Google clients — both Chrome and mobile apps — to Google servers.

These benefits are even more apparent for video services like YouTube. Users report 30% fewer rebuffers when watching videos over QUIC. This means less time spent staring at the spinner and more time watching videos.